Oil burner



Jan. 11, 1938. H. E. WOOLERY OIL BURNER Filed Sept. 12, 1936 INVENTOR.#OR/ICE E. WOOL S/?Y A TTORNE Y.

Patented Jan. ll, 1938 UNlTED STATES PATENT OFFICE OIL EURNER Horace E.Woolery, St. Paul, Mimi.,

Application September 12, 1936, Serial No. 100,480

iz oaims.

This invention relates to oil burners, and the main object is to providemeans ola novel, efcient, and practice] nature for preheating andmaintaining at 'a predetermined temperature the fuel spray nozzle of theburner whereby the fuel oil passing through the nozzle may be heated toa degree that will, facilitate flowage, vaporization, ignition, andcombustion, and thereby permit the use of relatively cruder and cheapergrades of commercial hydrocarbon fuel, which grades of fuel are known topossess high B. t. u. heat factors but which present difficulties toproper atomization and vaporization due to their dense and relativelyheavy consistency. A further object is to design the preheating nozzlewith a heat conductive element at its forward end, which element willserve to protect the electric heater from heat radiated from thecombustion chamber, and will also serve to absorb such heat and conductit into the nozzle proper whereby the oil preheating action may becontinued under the infiuence of radiant heat from the fire box afterthe burner .has been functioning for a predetermined period and at whichtime the preheater may be de-energized. The preheater as hereindisclosed comprises an electric heating element intimately associatedwith the nozzle so as to directly heat the same, and the electriccircuit to the element is automatically opened and closed by athermostatically operated switch, which is also intimately associatedwith the nozzle so as to be responsive to the temperature conditionthereof. More specically the automatic switch is designed to open orbreak the circuit to the heating element when conditions are such as toinsure sufficient nozzle heating by radiant heat without assistance fromthe electric heating unit, and also to close the circuit to againenergize the heating unit either when the burner is again initiallystarted or when the radiant heat is insufljciently intense to maintainthe desired nozzle temperature during normal functioning of the burner.

The present structure embodies various features which are illustratedand described in my co-pendng application Ser. No. 66,552, filed March2nd, 1936, for Oil burner, and to that extent the present application isa continuation, in part, of said earlier application.

In the accompanying drawing, which illustrates a preferred embodiment ofthe invention:

Fig. 1 is a side elevation of my improved nozzle Construction, withadjacent burner and furnace parts in section.

Fish 2 is a sectional elevation taken diametrically and longitudinallythrough the nozzle unit, with a portion broken away.

Fig. 3 is an enla-ged sectional elevation on the line 3-3 in Fig. 2.

Fig. 4 is a sectional detail elevation on line 4-4 in Fig. 2.

Referring to the drawing more particularly and by reference characters,5 designates the tubular front end portion of the burner unit housing,which housing extends through the fire box wall 6 of the furnace orboiler and opens at its front end into the combustion chamber 1 formedby such wall.

Disposed axially within the burner tube or housing 5 is a fue] supplypipe 8 which terminates in an enlarged portion forming the nozzle bodyproper 9, to which the fuel is fed from the pipe 8. A spray control headm is threaded into the front end of the nozzle and may be of anyconventional or suitable type capable of projecting the fuel in sprayform for combustion in the chamber l. The nozzle 9 is provided at itsforward end and about the head ill, with an integral, forwardly flaredannular fiange Il, which has for its primary purpose to absorb heatradiated from the combustion chamber '1 back through the front openingili of the tube 5, and to conduct such heat into the material of nozzle9 so as "to in turn increase or raise the temperature of oil in thenozzle chamber before such oil is projected through the control head loand into spray form within the combustion chamber '1. Another functionof the flange H is to prevent the aforesaid radiant heat from directlyimpinging upon and destructively eifecting the high resistance electricheating element l3 which annularly encloses the nozzle 9. This elementmay be of any suitable type, and extends from the fiange II rearwardlyto a second fiange or shoulder M, and is preferably provided with aninsulating cover !5.

The electric heating element !3 is connected by circuit wires l6 andll', to terminals !8 and |9 of the thermostatically operated switch, andthis circuit will also include a suitable current, source, and otherthermostat and control devices which may be found desirable to connectwith the burner apparatus.

The terminal point I 9 is adjustably Secured in an insulate cross bar 20mounted on a yoke 2| extending upwardly from tube 8, and the terminal l8is Secured in the insulate extension 22 of a lever 23 which fulcrums at24 to a stationary lug 25. A spring 26 tends to hold the long end of thelever 23 up with the terminals !8 and IS in contact with each other, inwhich event the circuit to the heating element is closed..

its forward end the lever 23 has a short depending arm for engagementwith an upstanding nger of a bar This bar is disposed a channel 38iormed longitudinally in the nozz-le material and the front end of thehar is Secured as at to the front portion of the nozzle. The bar 29 ismade of invar metal or some other material having a very low coeficientof expansion while the nozzle is ormed of metal having a relatively highcoefficient of eX- pansion, with a result that appreciable changes innozzle temperature will be effective to cause a longitudinal movementor" the bar nger 28, and when this occurs the mechanism will beoperative in association with the spring 28 to open and close thecircuit to the electric heating element.

The numeral 32 designates an electrode device for ign'ting the fuelspray discharged from the nozzle head m, and this device is connected upwith the ignition control mechanism so as to create an ignition spari;at the proper moment. The electrode design and its control mechanism,however, form not part of the present invention, and are therefore nothere disclosed or described in detail.

From the foregoing it will be understood that When energized the heatingunit 3 will be eperative not merely to heat the nozzle and fuel oiltherein to facilitate fiowage, but will do so immediately before suchfuel is to be projected from the spray head ill. This is an importantconsideration because when the burner is cold preheating of the fuel ata point spaced back of the point of dscharge will not assist to clearthe oil of thicler consistency which'has or may have previouslyaccumulated in the spray head. Et is of course desirable to provide acontrol mechanism which, for instance when a room thermostat calls forheat, will close the heating element circuit for a brief period beforethe fuel pressure and igm'tion mechanism is brought into play. This willinsure and acilitate initial flowage, vaporzation, ignition andcombustion. When the nozzle body or tube is heated to a predetermineclhigh degree of temperature, either by the electric heating element or bythe radiant heat of the combustion chamber acting on ange i i, then thethermostatic bar 29 will actuate the lever 23 to break the circuitthrough terminals i& and to deenergize the heater !3. Under ordinarycircumstances the absorbed radiant heat will thereafter be su'icient tomaintain the desired minimum nozzle temperature. Where,-however, such acondition does not prevail, then the resulting cooling of the nozzlewill automatically efiect reclosing of the heating circuit toagain'electrically heat the nozzle to the desired temperature, thusrestoring the oil preheating condition essential when using the cruderand heavier bodied hydrocarbon uel.

It is understood that suitable modifications may be made in thestructure as disclosed, provided such modifications come within thespirit and scope of the appended claims. Having now therefore fullyillustrated and described my invention, what I claim to be new anddesire to protect by Letters Patent is:

l. The combination with the fuel spray nozzle of an oil burner, of aneleotric heating element for heating said nozzle and the fuel therein tofacilitate atomization of the oil as it is projeeted in a spray from thenozzle, and thermally actuated means closely associated with so as to beresponsive to the temperature of the nozzle, for controlling a circuitto the electric heating element,

2. The combination with the !nel spray nozzle of an oil burner, of anelectric heating element for heating said nozzle and the fuel therein tofacilitate atomization of the oil as it is projected in a spray from thenozzle, a circuit for supplying the electric heating element, and means,responsive to the temperature of the nozzle, for automatically openingand closing the circuit When the temperature of the nozzle cools belowor is heated above an approximate predetermined degree.

3. The combination with the fuel spray nozzle of an oil burner, of anelectric heating element for heating said nozzle and the fuel therein tofacilitate atomization of the oil as it is projected in a spray from thenozzle, a circuit for supplying the electric heating element, a switchin the circuit, and thermostatically actuated means, arranged in aposition to be sensitive to the temperature of the nozzle, for openingthe switch to break said circuit.

4. The combination with the fuel spray nozzle of an oil bu'ner, of anelectric heating element for heating said nozzle and the fuel therein tofacilitate atomization of the oil as it is projected in a spray from thenozzle, a circuit for supplying the electric heating element, a switchin the circuit, and thermostatically actuated means, arranged in aposition to be sensitive to the temperature of the nozzle, forautomatically opening and closing the switch to thereby maintain apredetermined uniform nozzle temperature while the burner is beingoperated.

5. The combination with a burner nozzle, of means for heating the nozzleto facilitate vaporization of the fuel to be projected therefrom, a bardisposed longitudinally of the nozzle and attached at one end to thenozzle with its other end free to move longitudinally, said bar having adifferent coecient of expansion than the nozzle, and

means associated with said other end of the bar for controlling saidheating means.

6. The combination with a burner nozzle, of means for heating the nozzleto facilitate vaporization of the f uel to be projected therefrom, a.bar disposed longitudinally of the nozzle and attached at one end to thenozzle with its other end free to move longitudinally, said bar having adierent coeffcient of expansion than the nozzle, and means associatedwith said other end of the bar for controlling said heating means, saidheating means annularly enclosing the nozzle and bar.

'7. The combination with a burner nozzle of an electric heating elementextending annularly about the nozzle to heat the same, a circut forsupplying the heating element, a switch in the circuit, and athermostatically responsive strip disposed between the nozzle and saidheating element, said strip being assoclated with the switch to open thelatter when the strip is heated to a. 5

predetermlned temperature.

8. A fuel spray nozzle for an oil burner' comprising a. tubular memberterminating in 'an ejector head, said tubular member having a.longitudinal extending recess, an electric heating element disposedabout the nozzle and annularly enclosing said recess, a thermostatic bardisposed in said recess, so as to be responsive to the temperature ofsaid nozzle member, and extending at one end beyond the heating element,a. circuit for supplying the heating element, and a 75 switch in saidcircut operatively connected with said bar end for actuation thereby.

9. An oil burner having a nozzle for project ing fue] into a combustionchamber, and disposed with respect to the chamber in such manner as toreceive and absorb radiant heat therefrom, means other than said radiantheat for heating the nozzle, and thermally responsive means arranged tobe influenced by the temperature of the nozzle, for rendering inactivesaid nozzle heating mean&

10. An oil burner having a nozzle for projecting fuel into a eombustionchamber and dispose d with respect to the chamber in such manner as toreceive and absorb radant heat therei'rom, means other than said radiantheat for heating the nozzle, and thermally responsive means ar-= rangedto be influenced by the temperature of the nozzle, for renderinginactive said nozzle heating means, said nozze being provided at itsforward end with a fiared fiange facing the combustion chamber so as tofaclitate the absorbtion and conduction of such radiant heat to thenozzle.,

11., The eombination with an oil burner having a nozzle for projecting afue! spray into e. combuston chamber, of an electrc heating ele mentsurrounding the nozzle to heat the same and the fue] passingtherethrough, a flange mem ber projecting integrally and outwardly fromthe nozzle and forwardly of the heating element, to absorb heatradiating from the combustion charm ber and for transmitting such hee-tto the body of the nozzle, a 'thermostat circutously connected with theelectric heating element and arranged so as to be responsive to thetemperature of the nozzle, said thermostat being operative to controlthe circuit to said heating element.

12. The combnation with a nozzle for directing a fuel spray into acombustion chamber, of a heating element disposecl ahnularly about thebody of the nozzle, an annular flange extending in flared form forwardlyfrom the front end of the nozzle to absorb radant heat from thecombust'on chamber and Conduit it to said nozzle body, said flangeextending radially outwardly of the heating element to protect thelatter from direct action of such 'ad'ant heat.

HORACE E. WOOLERY.

